Zapping your skin with caffeine might work for some, but it won’t replace our coffee.

The folks at Sprayable Energy LLC must feel pretty good. They clobbered their crowdfunding goal on Indiegogo last year and got more than 10 times the amount of money they were looking for to finance production of their eponymous product, Sprayable Energy. According to its website, Sprayable wants its caffeinated spray to bring about "the end of tired." The idea is that you squirt a bit of odor-free aerosolized caffeine onto your skin and boom—you’re energized for hours. And this isn't any sudden-high-then-crash type of energy you get from coffee or other ingestible caffeine sources—Sprayable promises a "constant stream" of energy.

Sprayable reached out to Ars and requested that we give their product a review. We don’t respond to the vast majority of pitches that show up in our inboxes (and, man, there’s probably an awesome Ars feature story on "insane things that appear in Lee’s inbox"), but the premise here sounded intriguing. Who couldn't use a little pick-me-up throughout the day?

Wednesday evening, Sprayable Energy arrived. It came in a small foil pouch with a very official-looking "Drug Facts" label on the back—which you can see here. Inside the foil pouch was a black 8mL tube of product. It’s got a neat mechanism wherein you twist the bottle and the spray head telescopes up, though ours arrived with a pretty significant scratch on the spray head.

Before exposing myself to yet another chemical substance for Ars, I took a moment to read the label. The active ingredient in Sprayable Energy is (surprise!) caffeine, but not just any caffeine— "Caffenium 1XHPUS," the label said. And below that, "The letters 'HPUS' indicate that the components in this product are officially monographed in the Homeopathic Pharmacopoeia of the United States."

Uh oh. Is this stuff homeopathic?

A quick reminder: homeopathy is garbage

Without going down too deep a rabbit hole, recall that homeopathy purports to be the study of "like cures like"—homeopaths hold that diseases or afflictions within the body can be treated by introducing substances that cause similar effects within the body, thus marshaling the body’s own defenses and healing mechanisms.

According to homeopathy, water's selective memory saves you from drinking poo every time you raise a glass.

Aurich Lawson

Substances used in homeopathic remedies vary, but practitioners have their own rules and books and recipes for concocting cures. A common tenet of modern homeopathy, though, is that repeated dilution of curative substances in water magnifies the curative effect of the substance. So, for example, if you find yourself suffering for arsenic poisoning and you stumble into a homeopathic clinic for treatment, you’d likely be dosed with arsenicum album, which is a solution of deadly arsenic trioxide diluted so many times that the stuff you’d be given is statistically unlikely to actually contain even a single molecule of arsenic. Arsenicum album is also recommended by homeopaths for treatment of patients who are restless, tense, or who have a generally pessimistic outlook. Convenient!

This supposedly works because water has a memory. When properly prepared by a homeopath, the arsenicum album medicine "remembers" the arsenic it once mixed with. In fact, the more diluted it is, the stronger the effect the medicine is supposed to have on the patient. Fortunately, water’s memory is highly selective and only works under very specific circumstances—because otherwise, we would all be constantly dosing ourselves with ludicrously high homeopathic amounts of feces and heavy metals and radioactivity and who even knows what else—straight out of our drinking water!

Fortunately, homeopathy is total bullshit. Every last bit of it. Belief in homeopathy is belief in (to borrow a quote from Gene Wolfe) "the most debased and superstitious kind of magic." No homeopathic remedy has ever outperformed a placebo in any properly conducted test, full stop.

Energy in a bottle

Which brings us back to Sprayable Energy. We explicitly asked Sprayable Energy tech founder Ben Yu about the labeling on the bottle: is Sprayable Energy a homeopathic product, and does the company claim any of its efficacy is due to homeopathic principals?

"No, none of the efficacy is derived from homeopathic principals and completely complies with the generally accepted laws of science and nature," he responded, to our relief. "Were we to be an ingested product, we could easily be classified as a dietary supplement like 5 Hour Energy or Red Bull. That said, we fall fully under the guidelines for classification as a homeopathic product... it's a regulatory category that works for us that we can be in full compliance with, just like many other topical caffeinated products such as Spot On Energy."

With that statement settled, we dug into the actual caffeine content. Our initial thought was that the "1X" dilution notation on the 8mL bottle meant that the bottle contained 8mL of a 10:1 dilution of caffein in water (per typical homeopathic dilution labeling), but it turns out that it's much more complicated than that. Since caffeine is soluble at about 2 grams per 100ml of room-temperature water, or 2.2mg per each milliliter, the most dissolved caffeine that 8mL of room-temp water can hold would be 18mg; at a 1:10 dilution, that would be 1.8mg.

However, Sprayable Energy claims that it has a patent-pending method for increasing the solubility of caffeine in water by a factor of five, one documented in patent application PCT/US2014/02215 (we were unable to locate the patent application online, but Sprayable Energy provided us with a copy). According to Yu, this increase in caffeine's solubility is achieved by adding tyrosine isopropyl ester hydrochloride to the solution, which encapsulates the caffeine molecules in a micelle.

"As the tyrosine ester is much more soluble in water," explained Yu, "it in turn allows us to increase the solubility of caffeine in water by a factor of about five. Moreover, as the tyrosine ester is also more transdermal than caffeine, it acts to amplify the penetration rate of caffeine through cell membranes (and consequently skin cells) by a similar factor of around 3-4."

As for that "1X" homeopathic dilution label, Yu explains it thusly: "The 1X dilution isn't a dilution on top of the maximum amount of caffeine soluble in the solution—it just means that no more than 10 percent of the final solution can be caffeine—so up to ~800mg in 8mL."

Between the increased solubility and the dilution, how much caffeine are we talking about in this bottle? Yu says that Sprayable Energy aims to give people a dose of about 12.5mg of caffeine per application; with one application being four sprays, and with a bottle holding 160 sprays, this gets us about 500mg of caffeine in a single tube. Each spray should zap a bit more than 3mg of ester-encapsulated caffeine onto your skin.

Intake

Thursday morning, I stumbled out of bed as usual, but instead of making my way to the kitchen to for my usual coffee grind and press routine, I grabbed the tube of Sprayable Energy and blasted four sprays of the stuff against my neck, then two more against each wrist for good measure (the neck and wrists are the two recommended application sites). Then I flopped my way into the office, dropped like a thing dead into my chair, and waited. After 30 minutes, I wasn't feeling energized—I was feeling like how I feel when I don't get coffee in the morning. I sprayed myself 16 more times on the neck and wrists, bringing me up to the maximum recommended 24-spray dose.

Like most Americans, I know I should get more sleep; I rely on caffeine to provide me with a false sense of jittery alertness in the morning to mask how long it usually takes for me to wake up (because, recall, caffeine doesn’t actually give you energy or make you "less tired." It merely masks fatigue). It’s possible, then, that I’m too tired for Sprayable Energy’s small caffeine dosage to really do much—or I'm too caffeine-dependent.

According to Yu and also to our Sprayable Energy PR contact, the product's caffeine payload is deliberately low—12.5mg, for example, is still less caffeine than you might get in a cup of decaf coffee. However, that low dosage might be better at focusing the mind and banishing tiredness than the order-of-magnitude-larger dose you'd get with a big mug of coffee; at least, so says a research paper from the University of Bristol. Yu pointed out to us that, in the study, doses of 12.5mg of caffeine had "exactly the same effect on cognitive performance" as 100mg doses.

"Ingesting more caffeine will certainly make you feel more buzzed, jittery, and physically stimulated, but it does absolutely nothing to enhance your cognitive state," he said.

I don't drink a huge amount of caffeine throughout the day; I think the last time more than a sip or two of soda passed my lips was probably some time before the year 2000. However, I do love my morning coffee. I am a two-cup person—actually, about 2.25 cups (550 or so ml), according to the measurement I just did of my french press, and into those 2.25 cups typically goes a total of about 40g of beans (I'm not too proud to use beans from the grocery store, but I do grind them myself, because I am not a savage). I don't know how much caffeine that is, but I'd wager it's somewhere north of what I was getting transdermally from Sprayable Energy.

If dermal absorption of caffeine is even a thing, that is.

Through the cell wall

Whether or not caffeine can be effectively absorbed by the skin is an unsorted issue. Several years ago, we had Managing Editor Eric Bangeman lather himself up in with caffeine-infused soap, and at the time our science team expressed skepticism:

In conversations with the crack Ars scientific staff, Dr. Gitlin and Dr. Timmer both expressed doubt as to how well caffeine could be absorbed through the skin. They informed me that while the molecule is very water-soluble, which allows it to be easily absorbed by the body when it is consumed, it would have a much more difficult time making it through the skin.

Further Reading

Does caffeinated soap really give you enough buzz for the buck? We decided to …

However, as noted above by Yu, that's the problem the tyrosine ester was introduced to solve. The patent application has a whole lot of science-y diagrams in it and appears (to my non-science-y eyes) to substantiate or at least elaborate on what Yu summarized for us. The ester encapsulates the caffeine, and since the ester is much more amicable to being absorbed through the skin, it carries the caffeine with it.

Regardless of the theoretical efficacy of dermal caffeine absorption, after waiting a total of 45 minutes (30 after the initial dose and 15 for the second), I concluded that the spray was doing nothing for me. I was most decidedly not feeling the "constant stream of energy" that early users reported on the Indiegogo page. I gave up, went back into the kitchen, and made coffee.

Enlarge/ My coffee corner. This is what lets me face each day. (Most of the stuff here I bought based on TheSweetHome's recommendations.)

Lee Hutchinson

Cost, availability, and verdict

It's possible that I am simply over-conditioned to caffeine. In spite of only really having it once per day, I'll freely admit that I use quite a few beans in my press (but if I use less, the coffee doesn't taste as good). Yu told us that one of the things he wants to do with Sprayable Energy is free people from the rise and crash cycle brought about by over-ingestion of caffeine. "One of the fundamental goals behind Sprayable Energy is to end that cycle," he explained to Ars.

Fortunately, Yu and the other folks behind Sprayable Energy don't appear to buy into the insanity of homeopathy, in spite of the product's labeling. Still, I almost tossed the tube in the bin when I saw "homeopathic spray" on the side. Until Yu clarified that there was actually caffeine in the bottle, I thought a major reason why it didn't work was due to the fact that I saw "homeopathic" on the label and accidentally inoculated myself against the placebo effect.

Yu provided Ars with feedback from several hundred early Sprayable Energy users; about 90 percent of them said that they'd buy the product again, so it clearly had some kind of impact on a not-insignificant number of people. Still, for this reviewer, Sprayable Energy didn't do much of anything. If you want to give it a try yourself, though, you can get it for $15 per bottle direct from the manufacturer.

Verdict: Save your money. If you think you need this product to get through your day, I'd say it's likely that you already drink too much caffeine for it to have any effect on you—assuming that the underlying mechanism of delivery actually functions as advertised and it works at all. Actually, you know what else you can get for $15, once you add in tax and shipping? An awesome N7 mug like mine, for drinking actual coffee to get many, many milligrams of caffeine into your body.

It seems like an absurdly small amount of caffeine for $15, as you say. There single coffees from Starbucks that include more caffeine than that entire tube.

It's interesting that they looked the research and found that small amounts have the same effect as large amounts. But, as you say, there isn't much support that caffeine can be effectively absorbed in the skin.

Plus, I enjoy coffee.

Quote:

Considering one coffee cup is roughly 90-100 mg of caffeine, it would take about 30+ sprays to get the equivalent of one cup.

A 5.5oz cup of strong French press would be more like 180. And coffee cups are measured in 5.5oz quantities so the average person drinks more cups of coffee than they estimate.

Lee, for example, probably drinks 18 ounces per day which measures over three coffee cups and as much as 500mg of caffeine.

Cool, another product we don't need. Right up there with 1-wheel motorcycles and giant fan-hoverboards useful only on the Bonneville Salt Flats. If there is anything less in need of improvement than coffee as a caffeine vehicle, I can't think of it.

Lee, for example, probably drinks 18 ounces per day which measures over three coffee cups and as much as 500mg of caffeine.

Yeah, a lot of it is mug size, too. My french press is a "four cup" model, but it produces about two mugs' worth of coffee. If I had smaller mugs, it'd be more cups. "A cup of coffee" is a variable measurement.

But, as noted, for me a standard morning quantity of coffee is one french press' worth, or two mugs, or about 5.5 cups (or 18 oz, or ~530mL).

A good part of coffee's "kick" is, in my opinion, psychological. For many people, brewing it is part of it. Regardless, there are factors such as the smell, the flavor, and the physical act of consumption. The instant "ahh!" of that first sip. Those are things that you can't spray on.

Sure, get sciency about it - we need that - but don't ignore the other components of the "kick."

It seems like an absurdly small amount of caffeine for $15, as you say. There single coffees from Starbucks that include more caffeine than that entire tube.

It's interesting that they looked the research and found that small amounts have the same effect as large amounts. But, as you say, there isn't much support that caffeine can be effectively absorbed in the skin.

Plus, I enjoy coffee.

Quote:

Considering one coffee cup is roughly 90-100 mg of caffeine, it would take about 30+ sprays to get the equivalent of one cup.

A 5.5oz cup of strong French press would be more like 180. And coffee cups are measured in 5.5oz quantities so the average person drinks more cups of coffee than they estimate.

Lee, for example, probably drinks 18 ounces per day which measures over three coffee cups and as much as 500mg of caffeine.

And as anyone who might consume that much caffeine in a day could tell you, missing a days caffeine brings some of the nastiest headaches mankind can have.

I have slowed way down on my caffeine consumption for this reason alone. On my weekends I realized I was truly addicted to the substance, and if I missed getting my daily dose on a weekend day, I was sure to get a brutal, migraine-level headache.

Which is why I would love to see a cocaine spray. At least I would get a little extra oomph for the price of an addiction.

Lee, for example, probably drinks 18 ounces per day which measures over three coffee cups and as much as 500mg of caffeine.

Yeah, a lot of it is mug size, too. My french press is a "four cup" model, but it produces about two mugs' worth of coffee. If I had smaller mugs, it'd be more cups. "A cup of coffee" is a variable measurement.

But, as noted, for me a standard morning quantity of coffee is one french press' worth, or two mugs, or about 5.5 cups (or 18 oz, or ~530mL).

I should add that my estimation for French press was off - the caffeine content is usually estimated for 8oz cups I guess and French press extracts less caffeine than drip brew. I was surprised to hear that.

I was really expecting a second half to this article where Lee gave the remainder to someone who wasn't a big caffeine user to test. If it works as an occasional pick-me-up for someone who usually doesn't drink much caffeine, that's still useful information to have.

It seems like an absurdly small amount of caffeine for $15, as you say. There single coffees from Starbucks that include more caffeine than that entire tube.

It's interesting that they looked the research and found that small amounts have the same effect as large amounts. But, as you say, there isn't much support that caffeine can be effectively absorbed in the skin.

Plus, I enjoy coffee.

Quote:

Considering one coffee cup is roughly 90-100 mg of caffeine, it would take about 30+ sprays to get the equivalent of one cup.

A 5.5oz cup of strong French press would be more like 180. And coffee cups are measured in 5.5oz quantities so the average person drinks more cups of coffee than they estimate.

Lee, for example, probably drinks 18 ounces per day which measures over three coffee cups and as much as 500mg of caffeine.

And as anyone who might consume that much caffeine in a day could tell you, missing a days caffeine brings some of the nastiest headaches mankind can have.

I have slowed way down on my caffeine consumption for this reason alone. On my weekends I realized I was truly addicted to the substance, and if I missed getting my daily dose on a weekend day, I was sure to get a brutal, migraine-level headache.

Which is why I would love to see a cocaine spray. At least I would get a little extra oomph for the price of an addiction.

Yeah, I'm crazy, and yes, I realize we can't have nice things...

The cool thing about caffeine addiction is that it only takes 3 days to nearly remove symptoms and within 15 days you have completely lost tolerance.

A good part of coffee's "kick" is, in my opinion, psychological. For many people, brewing it is part of it. Regardless, there are factors such as the smell, the flavor, and the physical act of consumption. The instant "ahh!" of that first sip. Those are things that you can't spray on.

Sure, get sciency about it - we need that - but don't ignore the other components of the "kick."

As someone who cannot stand the smell or taste of coffee, finds almost all soda disgusting and excessively carbonated, and went for most of my life without caffeine before discovering add-to-water energy drink mix, I can say that nothing about the preparation of coffee is necessary for the "kick" of caffeine.

That isn't to say that the ritual doesn't have psychological benefits, they just have nothing to do with the effectiveness of caffeine itself.

Wow, I hadn't heard of this before- checked out the indiegogo page, and the whole thing screams alt-medicine / sports drink / energy drink bullshit. Given the tiny amount of caffeine in each squirt, I have to wonder if the people gushing about it never drink caffeinated drinks normally or if it's just placebo.

Also ++ for your digression on why Homeopathy is also complete bullshit.

Nit pick:"No homeopathic remedy has ever outperformed a placebo in any properly conducted test, full stop."

I assume that you include standard frequentist statistics in the realm of 'properly conducted' tests. If so, then 5% of tests should find homoeopathy better than the placebo at p = 0.05.

This is pretty much the definition of the p-value: the probability that you'll accept your observed difference as a real difference, due to noise, when the null hypothesis is true and your experimental and control groups are actually the same.

Out of curiosity, Lee, the pic of your coffee nook contains a tube of sea salt. Does that have any thing to do with making coffee? Am I even worse at making "real" coffee than I thought?

A tiny pinch of salt added before the water helps the coffee to be less bitter, if you're using too-hot water, which I am—I boil and pour, rather than getting a thermometer and waiting for the water to be right at 195F or whatever the proper extraction point of coffee is supposed to be this week.

Edited to add—it doesn't make the coffee salty or anything, because that would be gross. It just makes it a bit less bitter. I could probably pay a lot more attention to temperature and time, but eh.

Out of curiosity, Lee, the pic of your coffee nook contains a tube of sea salt. Does that have any thing to do with making coffee? Am I even worse at making "real" coffee than I thought?

A tiny pinch of salt added before the water helps the coffee to be less bitter, if you're using too-hot water, which I am—I boil and pour, rather than getting a thermometer and waiting for the water to be right at 195F or whatever the proper extraction point of coffee is supposed to be this week.

Edited to add—it doesn't make the coffee salty or anything, because that would be gross. It just makes it a bit less bitter. I could probably pay a lot more attention to temperature and time, but eh.

Interesting. I'm currently a "put Folger's in the pot and drink what comes out" person, but I've been interested in how other people do things, and plan to eventually switch to brewing my coffee like a civilized person.

I don't know about you guys, but I'm ready for that "Insane pitches Lee gets" article. Nothing on Ars makes me bust up like his willingness to share it all, to the point that I have a Pavlovian mad-grin reaction when I see his name on a new article now.

The most likely explanation for those satisfied customers is that the ignored the instructions on the label and did the obvious thing: sprayed the stuff in their mouths.

Without lab tests showing that sprayed-on caffeine is absorbed into the blood, there's no reason to expect that it would work, no matter how much chemistry talk the promoters brought to the table.

That could be. I'm a contracted independent information researcher for the FDA, I see these types of claims all the time, sometimes I get to actually interview the so called 'satisfied customer'. There are many homeopathic products on the market that make claims of chemistry and science and satisfied customers with various testimonials that claim this or that stupendous or fantastic or satisfying result. Once the research is done and the digging deep, for most of these products its usually found the 'satisfied customers' are actually in very few numbers and the results are psychosomatic, sometimes we find the "satisfied customers" are actually paid or compensated, or promised something, in some way to give their 'testimonials' but actually had no result at all from using the product.

People at my work think I'm crazy because I drink so much coffee. They're guzzling these $2 Monster drinks that taste like fruit-flavored ass and have a fraction of the caffeine of the completely free drip brewed coffee that I nurse all day long.

People at my work think I'm crazy because I drink so much coffee. They're guzzling these $2 Monster drinks that taste like fruit-flavored ass and have a fraction of the caffeine of the completely free drip brewed coffee that I nurse all day long.

The problem with coffee for a lot of people is it's not exactly thirst quenching.

Coming from some one who drinks 8 or 9 monsters a day averaging about 120mg of caffeine per can 240mg if I get the 24 ounce cans I cannot think of a viable alternative (legal that is im sure meth would put some nos in my tank) would be nice to see something else that worked because these bloody energy drink are killing both me and my bank account.

I've tried SE twice - both times, while it didn't provide any sort of jolt, I did notice that I didn't have my usual post-lunch afternoon "letdown."

I have no way of knowing for sure if it was the placebo effect or whether it genuinely stimulated me, but after about 30 minutes I wasn't feeling as rundown as I usually do in the afternoon. Of course, YMMV.

Coming from some one who drinks 8 or 9 monsters a day averaging about 120mg of caffeine per can 240mg if I get the 24 ounce cans I cannot think of a viable alternative (legal that is im sure meth would put some nos in my tank) would be nice to see something else that worked because these bloody energy drink are killing both me and my bank account.

An early grave awaits. Not from all the caffeine, but a daily intake of that much sugar ain't gonna do you any good.

My advice would be to switch to Coke zero or similar if you need a sweet tasting caffeinated fix. It certainly saved my waistline when I switched to a more sedentary occupation.

Coming from some one who drinks 8 or 9 monsters a day averaging about 120mg of caffeine per can 240mg if I get the 24 ounce cans I cannot think of a viable alternative (legal that is im sure meth would put some nos in my tank) would be nice to see something else that worked because these bloody energy drink are killing both me and my bank account.

8 or 9 a day and your heart hasn't exploded yet? You do know the daily recommended maximum for those things is like 2 right? I think it says that on some cans.

That's a marketing statement, it takes a lot more than that to make your heart go splodey unless you have advanced heart disease. 1000+mg caffeine a day is not great, probably at the point where it barely affects anything but your bladder anymore, and it's time to detox so you can get your sensitivity back. (Yes, that means a few days of migraine hell.) Its only significantly negative effect is going to be on your liver and kidneys. You'd need far more to put your brain on the fritz (which is what messes with your heart), unless you had no tolerance at all, and a normal person would quit long before that point.

That said, there have been people who took no-doz until they had a stroke or heart attack. It's a lot easier to swallow a fistful of pills than a pallet of carbonated drinks.

And as anyone who might consume that much caffeine in a day could tell you, missing a days caffeine brings some of the nastiest headaches mankind can have.

I have slowed way down on my caffeine consumption for this reason alone. On my weekends I realized I was truly addicted to the substance, and if I missed getting my daily dose on a weekend day, I was sure to get a brutal, migraine-level headache.

Yup, I can vouch for that. That hangover feeling, without the alcohol.

An enforced stay in hospital recently got me over the caffeine hump. Swearing blind I'll not touch the stuff again now. We'll see how long that resolve lasts, though...

Lee Hutchinson / Lee is the Senior Reviews Editor at Ars and is responsible for the product news and reviews section. He also knows stuff about enterprise storage, security, and manned space flight. Lee is based in Houston, TX.